Unit 2: Nervous System: ANS

Question 1

Describe the different divisions of the peripheral nervous system (aka afferent & efferent)

Answer 1

Afferent [sensory] neurons - conveying info from sensory receptors towards CNS

Efferent [motor] neurons - conveying info from CNS to effectors (muscles or glands)

Question 2

The neurons found exclusively within CNS are known as :

Answer 2

integration neurons, association neurons, or interneurons

Question 3

Where does integration occur

(in terms of gross anatomy and in terms of cellular neuroanatomy)?

Answer 3

CNS

Synapses

Question 4

Describe the different ways neurons can be interconnected to produce simple neural circuits.

Answer 4

A. Linear- [signal transmitted is a chain reaction; ex) knee jerk reflex] ; simple.

B. -Divergent- 1 single sensory neuron results in activity in several somatic motor neurons; ex) stepping on a tack- crossed extensor reflex

-Convergent- multiple neurons converge onto fewer neuron; ex) rods/cones in the retina

C. Inhibitory- neuron becomes excited and AP arrives at synapse > NTs released produce inhibitory postsynaptic potential
[inhibitory neuron becomes excited and generates AP but neurons it synapses with produce IPSPs and are inhibited.

D. Parallel (W/ lateral inhibition)- a neuron’s response to a stimulus is inhibited by the excitation of a neighboring neuron

E. Reverberating- chain of neurons where signals travel in a loop>feedback loop; can sustain an impulse or rhythmic pattern of firing

Question 5

Define adrenergic (AKA catecholaminergic)

Answer 5

relating to nerve cells in which epinephrine (adrenaline) or norepinephrine (noradrenaline) acts as NT

Question 6

cholinergic

Answer 6

relating to nerve cells in which acetylcholine acts as NT.

Question 7

Muscarinic

Answer 7

type of NT receptor activated by acetylcholine (ACh).

associated with the parasympathetic nervous system

key role in regulating functions such as heart rate, smooth muscle contractions, and glandular secretions

Question 8

nicotinic

Answer 8

type of NT receptor activated by acetylcholine (ACh) or nicotine.

~They are ion channels that, when activated, allow the flow of ions across cell membranes, leading to electrical signaling and physiological responses.

Question 9

What are the 2 types of efferent (motor) neurons?

Answer 9

Somatic- specific to skeletal muscle

autonomic- associated with cardiac muscle, smooth muscle, and glands

Question 10

pre and post-synaptic neurons are characteristic of what pathway?

Answer 10

autonomic motor pathways (not associated with somatic or sensory pathways)

Question 11

Somatic NS is made up of ____________ ____________ that extend without synapsing from dendrites and cell bodies (in the CNS) all the way out to terminal endings that are synapsing onto skeletal muscles

Answer 11

multipolar neurons

Question 12

The autonomic NS is made up of ___________ _________ synapsing onto a post-ganglionic neuron

Answer 12

preganglionic neuron

Question 13

____________ are integration sites

Answer 13

synapses

Question 14

Autonomic NS- does NOT produce ________ control

Answer 14

voluntary

Question 15

preganglionic neurons are always:

Answer 15

Myelinated

Question 16

Pre-ganglionic neurons always have cell bodies and dendrites within the CNS and always terminate onto :

Answer 16

dendrites and cell bodies of 2nd neuron (W/ one exception)

Question 17

The primary ligand activates a receptor.
An ____1_____ also activates the receptor.
An _____2_____ blocks receptor activity.

Answer 17

1- agonist [mimic]

2- antagonist [blocker]

Question 18

Antagonist molecules _______ receptors

Answer 18

inhibit

[basically like competitive binding]

Question 19

in the parasympathetic NS, preganglionic neuron may originate from

Answer 19

the brainstem
or sacral part of the spinal card

[craniosarcal division]

Question 20

in the parasympathetic NS, pre-ganglion neurons are long and -

Answer 20

myelinated

Question 21

Sympathetic NS neurons arise from ______________________ parts of the spinal cord

Answer 21

thoracic and lumbar

Question 22

Sympathetic regulation causes heart to-

Answer 22

Speed up

[antagonistic influence on effector organs]

Question 23

Sympathetic stimulation has the ____________________ response

Answer 23

fight or flight

Question 24

3 circuits of sympathetic NS stimulation

Answer 24

1) short pre-ganglionic neurons that synapse in the paravertebral ganglion chain [may branch]

2) pre-ganglionic neuron extends out and synapses in the adrenal medulla

3) pre-ganglionic neuron synapses in a collateral ganglion

Question 25

The autonomic nervous system includes _____ neurons from the CNS to the effector.

Answer 25

two

Question 26

How neurons are interconnected in neural circuits can result in :

Answer 26

emergent properties not exhibited by individual neurons

Question 27

In the autonomic nervous system the neurotransmitter norepinephrine is secreted by _______.

Answer 27

postganglionic sympathetic neurons

Question 28

The strength of a stimulus determines the ____ of an action potential.

Answer 28

frequency

Question 29

Inhibitory neurons secrete:

Answer 29

neurotransmitters that trigger IPSPs

Question 30

In the peripheral nervous system, ________ 1 ________ carry sensory and visceral info >CNS

and ________ 2 ________ leave the CNS and innervate organs [usually muscles or glands]

Answer 30

1- afferent neurons

2- efferent neurons

Question 31

The sympathetic division of the autonomic nervous system is also called the:

Answer 31

thoracolumbar division

Question 32

Describe the structural and functional characteristics of the somatic division of the nervous system.

Answer 32

Structural Characteristics:

Somatic/ motor Neurons

Single Neuron Pathway

Voluntary Control

Functional Characteristics:

Motor Control

Sensory Feedback

One-Way Communication: signals flowing from the CNS to the skeletal muscles

Conscious Awareness

Fast Responses

Question 33

afferent neurons are typically ______________ neurons

Answer 33

pseudo-unipolar

Question 34

Afferent neurons transmit information from: __ to ___

Answer 34

the periphery to the CNS

Question 35

Where are nicotinic acetylcholine receptors found?

Answer 35

between the motor neurons of the somatic motor division and skeletal muscles

between the pre and post synaptic neurons of the sympathetic division

between the pre and post synaptic neurons of the parasympathetic division